Incorrect type definitions for `std::time::{SystemTime, Instant, Duration}`

[Vlad-Shcherbina]

SystemTime and Duration are serialized as two-field objects, not strings. Instant doesn't support serialization at all, see serde-rs/serde#1375.

[dependencies]
chrono = { version = "0.4.24", features = ["serde"] }
serde = { version = "1.0.163", features = ["derive"] }
serde_json = "1.0.96"
specta = "1.0.4"

#[derive(serde::Serialize)]
#[derive(specta::Type)]
struct MyStruct {
    st: std::time::SystemTime,
    // i: std::time::Instant,
    d: std::time::Duration,
}

fn main() {
    println!("{}", specta::ts::export::<MyStruct>(&Default::default()).unwrap());
    println!();
    let s = MyStruct {
        st: std::time::SystemTime::now(),
        d: std::time::Duration::from_secs(1),
    };
    println!("{}", serde_json::to_string_pretty(&s).unwrap());
}

export type MyStruct = { st: string; d: string }

{
  "st": {
    "secs_since_epoch": 1684393811,
    "nanos_since_epoch": 203204000
  },
  "d": {
    "secs": 1,
    "nanos": 0
  }
}

[oscartbeaumont]

Great spot will get these fixed and do a release!

Fixing this does raise an interesting question. From looking into Serde's codebase both SystemTime and Duration output basically { field1: u64, field2: u32 }. Now u64 is a "bigint" type which Specta's Typescript exporter doesn't support by default to prevent people from shooting themselves in the foot as JSON.parseing a bigint type can cause truncation.

By adding a "bigint" type to a default impl it would make the export feature of Specta useless unless you have bigint support enabled which is definitely not something I would want to do.

We could come up with a system so we can add this as an exception to the rule but that is also not really a prefect solution, alternatively we could require a feature to enable these impls but that also isn't perfect because you would kinda of expect all standard types to just work out of the box.

[oscartbeaumont]

After chatting with @Brendonovich he pointed out that the export system should lazily include standard library types which in hindsight is probably a bug. I have just fixed that. I have also decided that SystemTime and Duration are to be treated as "bigint" types given Specta's general focus on correctness.

If you include a SystemTime or Duration in your schema you will be required to specify how you want to handle them through BigIntExportBehavior. Will try and do a release this afternoon with these changes.

[avsaase]

What is the current state of this? I'm generating Typescript types for a rust struct that has a Duration field and on the TS side I'm getting a string with value [object Object].

[oscartbeaumont]

Should be supported in 1.0.5 so update your project.

@avsaase What do you mean by [object Object] because I don't think that is something Specta is capable of outputting?